afh.h

   1 /*
   2  * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file afh.h structures for audio format handling (para_server) */
   8
   9 /** \cond */
  10 #ifdef HAVE_OGGVORBIS
  11 #define OV_AUDIO_FORMAT " ogg"
  12 #else
  13 #define OV_AUDIO_FORMAT ""
  14 #endif
  15
  16 #ifdef HAVE_FAAD
  17 #define AAC_AUDIO_FORMAT " aac"
  18 #else
  19 #define AAC_AUDIO_FORMAT ""
  20 #endif
  21
  22 #define SUPPORTED_AUDIO_FORMATS "mp3" OV_AUDIO_FORMAT AAC_AUDIO_FORMAT
  23
  24 /** \endcond */
  25
  26 /**
  27  * The tags used by all audio format handlers.
  28  *
  29  * Paraslash only uses the more common tags. These are recognized
  30  * for all supported audio formats.
  31  */
  32 struct taginfo {
  33         /** TPE1 (id3v2) / ARTIST (vorbis) / ©ART (aac) */
  34         char *artist;
  35         /** TIT2/TITLE/©nam */
  36         char *title;
  37         /** TDRC/YEAR/©day */
  38         char *year;
  39         /** TALB/ALBUM/©alb */
  40         char *album;
  41         /** COMM/COMMENT/©cmt */
  42         char *comment;
  43 };
  44
  45 /** Audio format dependent information. */
  46 struct afh_info {
  47         /** The number of chunks this audio file contains. */
  48         long unsigned chunks_total;
  49         /** The length of the audio file in seconds. */
  50         long unsigned seconds_total;
  51         /** Audio handler specific info about the file. */
  52         char *techinfo;
  53         /** Id3 tags, vorbis comments, aac tags. */
  54         struct taginfo tags;
  55         /**
  56          * The table that specifies the offset of the individual pieces in
  57          * the current audio file.
  58          */
  59         uint32_t *chunk_table;
  60         /** Period of time between sending data chunks. */
  61         struct timeval chunk_tv;
  62         /**
  63          * The position of the header within the audio file. Ignored if \a
  64          * header_len equals zero.
  65          */
  66         uint32_t header_offset;
  67         /**
  68          * The header is needed by senders in case a new client connects in the
  69          * middle of the stream. The length of the header defaults to zero
  70          * which means that this audio format does not need any special header
  71          * treatment. The audio format handler does not need to set this to
  72          * zero in this case.
  73          */
  74         uint32_t header_len;
  75         /** The number of channels. */
  76         uint8_t channels;
  77         /** Frequency in Hz. */
  78         uint16_t frequency;
  79         /** Exact meaning depends on audio format. */
  80         uint16_t bitrate;
  81 };
  82
  83 /**
  84  *  Structure for audio format handling.
  85  *
  86  *  There's one such struct for each supported audio format. Initially, only \a
  87  *  name and \a init are defined. During the startup process, para_server calls
  88  *  the \a init function of each audio format handler which is expected to fill
  89  *  in the other part of this struct.
  90  */
  91 struct audio_format_handler {
  92         /** Name of the audio format. */
  93         const char *name;
  94         /**
  95          * Pointer to the audio format handler's init function.
  96          *
  97          * Must initialize all function pointers and is assumed to succeed.
  98          */
  99         void (*init)(struct audio_format_handler*);
 100         /** Typical file endings for files that can be handled by this afh. */
 101         const char **suffixes;
 102         /**
 103          * Check if this audio format handler can handle the file.
 104          *
 105          * This is a  pointer to a function returning whether a given file is
 106          * valid for this audio format. A negative return value indicates that
 107          * this audio format handler is unable to decode the given file. On
 108          * success, the function must return a positive value and fill in the
 109          * given struct afh_info.
 110          *
 111          * \sa struct afh_info
 112          */
 113         int (*get_file_info)(char *map, size_t numbytes, int fd,
 114                 struct afh_info *afi);
 115 };
 116
 117 void afh_init(void);
 118 int guess_audio_format(const char *name);
 119 int compute_afhi(const char *path, char *data, size_t size,
 120         int fd, struct afh_info *afhi);
 121 const char *audio_format_name(int);
 122 void afh_get_chunk(long unsigned chunk_num, struct afh_info *afhi,
 123                 void *map, const char **buf, size_t *len);
 124 uint32_t afh_get_largest_chunk_size(struct afh_info *afhi);
 125 void afh_get_header(struct afh_info *afhi, void *map, const char **buf, size_t *len);